The ICU has since been fighting government forces, its Ethiopian allies and African Union troops.

Separately, on Wednesday, a truck driver contracted by the World Food Programme (WFP), was shot dead in central Somalia by a gunman who opened fire at a convoy of trucks ferrying food.

Peter Goossens, the WFP's director for Somalia, said in a statement: "We condemn this senseless killing and once again urge all parties to ensure the safe passage of humanitarian staff and cargo across the country."

Violence has disrupted the delivery of aid to hundreds of thousands of internally displaced civilians in the country.

Humanitarian groups are struggling to feed at least two million people in Somalia, which is experiencing a prolonged drought and record high inflation.